Polymers and polymeric material that include UV absorbers are known in a wide variety of applications. For example, U.S. Pat. No. 5,376,650, to Weaver et al., adentitled "Light Absorbing Polymers", discloses light-absorbing thermoplastic polymer compositions for imparting color and/or UV protection to thermoplastic resins. U.S. Pat. No. 4,668,739, to Berdahl et al., entitled "Poly(Phenylene Ether)-Bound UV Absorber", teaches stabilized polyphenylene ether resins incorporating UV absorbers, which are useful as high performance engineering thermoplastics in the production of films, fibers and molded articles. U.S. Pat. No. 5,385,815, to Schofield et al., entitled "Photographic Elements Containing Loaded Ultraviolet Absorbing Polymer Latex," describes polymers formed from ethylenically unsaturated monomers having pendent UV absorbers, which are useful in protecting silver halides in photographic elements from exposure to UV.
Polyurethanes, polyureas and combined polyurethane/polyureas have been used in the production of biomedical devices, in particular devices, such as glucose sensors, which are implantable in a human patient. For example, U.S. Pat. No. 5,165,407, to Wilson et al., entitled "Implantable Glucose Sensor", teaches a glucose sensor which is fabricated using a polyurethane coating layer. In certain known manufacturing processes for the production of such sensors, the sensors are produced by sequential buildup of the sensor layers on a substrate. The completed sensors are finally removed from the substrate by use of a laser, which cuts the sensors from the remaining laminate atop the substrate. Known polyurethanes, however, are substantially transparent at the laser wavelengths typically employed (355 nm, in the ultraviolet region of the spectrum), unlike other polymers, such as polyimide (the UV absorption spectrum of which is shown in FIG. 5), which also form layers of the laminate. This substantial transparency results in processing difficulties.
A need exists for a polymer that is strongly UV absorbent. A need also exists for a polymer, in particular a polyurethane, polyurea or polyurethane/polyurea copolymer, that absorb UV in the same range as other polymers, such as polyimides, that are used in the production of thin film sensors. More specifically, a need exists for a polymer that absorbs UV in the 355 nm range.
A need also exists for a UV-absorbing polymer that is biocompatible, in order to permit use in the production of implantable sensors such as blood glucose sensors.